Jog dials are commonly used as an interface of a controller that operates to control playback positions of video data or sound data in searching for a desired playback position of video or sound while playing recorded video or sound data and looking at video or listening to sound (see Patent Document 1, for example). A jog dial is configured to move the playback position according to a rotational position of a dial as an operation unit operated by a rotating operation. The jog dial is an interface that can be easily operated in an intuitive manner, and while it is convenient when a playback position of intended video or sound is temporally close to a current playback position, it is not suitable for a case in which the playback position of the intended video or sound is temporally far from the current playback position, as it is necessary to continue the rotating operation for a while.
Therefore, many jog dials that are conventionally used are provided with, in addition to a normal “jog mode” for moving a playback position according to a rotation speed at which the jog dial is rotated, a “shuttle mode” for changing the playback speed according to an angle at which the jog dial is twisted, and are configured such that the playback speed is increased by rotating the dial after switching to the shuttle mode when the playback position of the intended video or sound is temporally far from the current playback position.
However, there is a problem in that, when such a conventional jog dial is in the shuttle mode, if the jog dial is operated assuming that it is in the jog mode by mistake, the playback speed is increased to a large degree and the playback position is moved far away from the intended position, thus consuming excessive time and effort to move the playback position back to the original position. This is critical when time is limited, especially in such a case when preparing replay in a live sport broadcast.
There is still an additional problem in that, in the shuttle mode, unlike the jog mode, the playback position can be overly moved before stopping the playback, since it is necessary to rotate the dial to adjust to a stop position or to press a stop button between when a video image is found and when the playback is stopped.
While there is a product that allows access to both functions at the same time by providing a ring for shuttle operation outside of the jog dial, this adversely limits a hand position on the jog dial, since it is not possible to place the hand on the side of the jog dial due to the ring. There is another product with which an amount and the speed of rotation of the jog dial can be switched by buttons, but this adversely takes time and effort in switching of the buttons.
There is also a product that can increase the speed by continuing rotation of the jog dial (see Patent Document 2, for example). However, this can turn out to be more inconvenient in some cases, since the speed may be unintentionally increased when intending a preview playback at a constant speed.